MD21 Reverse Gear Not Engaging

I just replaced the Volvo Pent

I just replaced the Volvo Penta MD21a in my sailboat with a MD21b and got it running today. I kept the original Volvo RB reduction reverse gear that was on the original engine. Now it will not engage in forward or reverse and doesn't make any noise to indicate that it is even trying.

I manually moved the selector arm on the tranny into what should have been forward and reverse and the prop shaft moves forward and back as I do this. There is no change in engine revs or sounds from the tranny that indicate that something is happening (Or not happening). The lever shifts easily and seems to go into the correct positions but nothing. I checked the oil and it was low but clean. Topped it off and checked again and it still did the same thing.

I did move the boat with the tranny still in and the engine out before installing the new engine. The guy towing me had us going pretty fast and I don't know if it was in neutral or in gear. Could this have done anything to the tranny?

Anybody have any ideas?

Did You by any chance forget t

Did You by any chance forget to shift over the vibration damper from the old to the new engine?

I did not. The new engine came

I did not. The new engine came with one on it. It also came with a bellhousing that was the same as what was on the old engine. I removed that and used the bellhousing from the original MD21a.

My manual for the MD21a shows that there are either two vibration dampers attached to the flywheel or two different types that are used. It's unclear.

Does the 21b use a different vibration damper than the 21b? Or were there several different options?

Thanks for your help.

Nick

"If Your replacement engine ha

"If Your replacement engine had a damper for MS3, it does not fit on the splines."

"Wouldn't that mean that I

"Wouldn't that mean that I wouldn't have been able to get the engine and tranny to fit together and bolt up? Perhaps the tranny shaft is too long and passes through the damper without engaging with it? I know that the shaft passed through it as it is bolted up.

I, unfortunatly, was manning the block and tackle and wasn't right there when they were going together.

I just checked the Volvo out of production product bulletins and saw that the MS3 has an 8 degree angle. It makes sense that it would have a different damper. I suppose I'll find out when I take them apart again.

Thanks,

Nick"

"Nick, RB used a small 8 splin

"Nick, RB used a small 8 spline shaft for input. MS3 used a large 26 spline shaft. Rb shaft went right through large hole. Need to change dampers."

"Although it is too late for t

"Although it is too late for this advice but it is usually a good idea to remove the dampener plate and fit it on the gearbox spline before finally installation, even when new. I had one that was the correct size and all but the end was slightly burred and would not slide in. It was a bad location to work in the first place. This made it very frustrating. After removing it and de-burring, it slid easily."